1. Field of the Invention
The present invention relates to a steam generator and a laundry machine having the same, and more particularly to a steam generator and a laundry machine having the same which can prevent malfunction of a water level sensor which measures a water level.
2. Discussion of the Related Art
Generally, a laundry machine includes a washer for washing clothes and a dryer for drying wet clothes.
A washer is classified into a pulsator type washer which washes laundry by water current generated by rotating a pulsator, and a drum type washer which washes laundry by drop and frictional force of washing water and laundry generated by rotating a horizontally mounted drum.
A dryer dries wet clothes by supplying hot air to wet clothes.
Recently, a drum type washer which washes laundry by using steam has been proposed. If using steam for washing laundry, water and electricity can be saved, and washing performance can be improved. Also, creases and odor can be removed.
A conventional drum type washer using steam will now be described with reference to FIG. 1.
The conventional drum type washer includes a cabinet 10 which forms an external appearance, a cylindrical tub 20 which is horizontally mounted in the cabinet 10 and contains washing water, a drum 30 which is rotatably mounted in the tub 20, and a driving motor (not shown) which drives the drum 30. The cabinet 10 is provided with an opening 13 at a front panel, which is communicated with the inside of the drum 30 for putting laundry into the drum 30 and taking laundry out of the drum 30, and a door 11 for opening and closing the opening 13. The drum type washer further includes a water-supply valve 15 which is connected to an external water pipe (not shown) to supply washing water into the tub 20. A hot-water pipe 25a and a cold-water pipe 26 extend from the water-supply valve 15 to a detergent box 27.
The drum type washer further includes a steam generator 50 for supplying steam into the drum 30. A water-supply hose 25 and a steam-supply pipe 53 for guiding the generated steam into the drum 30 are connected to the steam generator 50. The water-supply hose 25 is typically connected to a hot-water side of the water-supply valve 15. The steam-supply pipe 53 has a nozzle-shaped front end so as to effectively inject steam into the drum 30, which is exposedly mounted to the inside of the drum 30.
Referring to FIGS. 2 and 3, a structure of the steam generator 50 will now be described in detail.
The steam generator 50 includes a housing 80 which has a lower housing 81 which forms an outer appearance and provides a space for storing water and an upper housing 82 which is coupled to an upper portion of the lower housing 81, and a heater 55 which heats the water stored in the housing 80.
The upper housing 82 is formed with a water-supply port 52a to which the water-supply hose 25 is connected to guide the water into the housing 80, and a discharge port 52b to which the steam-supply pipe 53 is connected to supply the generated steam into the drum 20.
The heater 55 is mounted to a lower portion in the lower housing 81 so as to be immersed in the water flowing into the housing 80 of the steam generator 50. In order to operate the heater 55 while the heater 55 is immersed in the water, a water level sensor 60 is mounted to the upper housing 82 of the steam generator 50. The water level sensor 60 measures the water level in the housing 80, so that the water level in the housing 80 can be always kept to an adequate level. In other words, when the water level in the housing 80 of the steam generator 50 is less than a preset reference level, the water-supply valve 15 is opened to supplement water. When the water level in the housing 80 is the reference level or more, the water-supply valve 15 is closed to stop the water supply, and the heater 55 is operated to generate steam.
Also, a temperature sensor 57 is mounted to the upper housing 82 of the steam generator 50 to measure temperature of the water heated by the heater 55 and the steam. When the temperature measured by the temperature sensor 57 is a preset reference value or more, the power applied to the heater 55 is interrupted to prevent overheating of the heater 55.
Describing the water level sensor 60 in detail, the water level sensor 60 includes a receptacle housing 61 which forms an outer appearance and is configured to be fixed to the upper housing 82 of the steam generator 50, and electrode parts 62, 63 and 64 which are mounted downward at the receptacle housing 61 and sense the water level in the housing 80 of the steam generator 50.
The electrode parts 62, 63 and 64 extend downward from the receptacle housing 61 to respectively adequate heights from a bottom of the lower housing 81.
However, the above steam generator of the conventional washer has a problem of high possibility of malfunction of the water level sensor. The reason is as follows.
The water level sensor measures the water level in such a manner that when the electrode parts are immersed in the water, electric current flows. However, when the water is boiled by the operation of the heater, bubbles are generated and intensely spattered on inner walls of the steam generator. And, the bubbles rebound from the inner walls of the steam generator and are scattered in all directions, so that the bubbles get in touch with the electrode parts of the water level sensor and form water films thereon, thereby causing the malfunction of the water level sensor.
Also, when the water is supplied into the steam generator, a portion of water is spattered on the electrode parts, which also causes the malfunction of the water level sensor. Also, during the operation of the washer, vibration is generated and transmitted to the steam generator, so that the steam generator also vibrates to cause the water in the housing of the steam generator to slop from side to side to get in touch with the electrode parts of the water level sensor, thereby causing the malfunction of the water level sensor.